This study evaluated the effects of feeding varying levels of dietary DL-methionine (MET) supplementation on breast meat (BM) quality of broilers of different sex. The 1-day-old, sexed chicks (Ross 708, 1552) were randomly allocated into four groups (each with 4 replicates) and were raised with diets supplemented with 0, 0.5, 1, or 2 g MET/kg of feed to a common weight (2.72 kg). Color, pH, drip loss (DL), water-holding capacity, moisture uptake, cooking yield (CY), texture, total antioxidant capacity (TAC), and lipid oxidation (LO) were determined using BM samples harvested 24 h postmortem. The male BM had higher redness, TAC, firmness, and toughness but lower yellowness (p < 0.01) than the female BM. In both sexes, birds fed 0.5 g/kg MET had lower DL (p < 0.01) than those fed 1 and 2 g/kg MET. For storage up to 3 days, MET suppressed LO in cooked BM (p < 0.01) and suppression increased as MET increased. CY for 1 and 2 g/kg MET were higher (p < 0.01; 79.04 and 78.60%, respectively) than CY for 0 and 0.5 g/kg MET (66.18 and 68.03%, respectively). These results suggest that MET supplementation at 1 g/kg or higher for broilers can improve oxidative stability, muscle functionality, and breast meat CY.